Opening and closing device and electronic apparatus using the same

ABSTRACT

An opening and closing device and an electronic apparatus using this device. In an urging section, a movable member including a movable cam on its side is urged by a spring. A slide member includes, at one end, a stationary cam, opposed to the movable cam, for resiliently contacting the movable cam. The movable member is urged in opening and closing directions in open and closed states, respectively, according to which portion of the stationary cam resiliently contacts the movable cam. A reversing section includes a release member and a reversing member. The release member includes a release cam resiliently contacting a support cam at the other end of the slide member, and the reversing member is inserted into the slide member and includes a reversing cam. When the release cam is disconnected from the support cam, the slide member slides axially, whereby the movable cam is disconnected from the stationary cam and resiliently contacts the reversing cam. The direction that urges the movable member is thus reversed, changing from the closing to opening direction.

FIELD OF THE INVENTION

The present invention relates to an opening and closing device used inan electronic apparatus such as a portable telephone or a small personalcomputer and also relates to the electronic apparatus using this openingand closing device.

DESCRIPTION OF RELATED ART

Recently, an electronic apparatus such as a portable telephone or asmall personal computer has become increasingly smaller, morelightweight and more functional. The number of so-called foldingelectronic apparatuses, each of which has a movable housing mounted to astationary housing so as to be able to open and close, has grown, and inthese electronic apparatuses, opening and closing devices are used tofacilitate the opening and closing operation.

An example of the conventional opening and closing device and theelectronic apparatus using this device will be described hereinafterwith reference to FIGS. 9–12.

FIG. 9 is a sectional view of the conventional opening and closingdevice.

FIG. 10 is an exploded perspective view of the same opening and closingdevice.

In FIGS. 9 and 10, cylinder 1B of movable shaft 1 is passed throughcentral through hole 2B of movable casing 2. End 1A of movable shaft 1is locked to stepped part 2A at a right side of movable casing 2,whereby movable shaft 1 is fixed to movable casing 2. Movable shaft 1 ismade of metal, and movable casing 2 is substantially cylindrical andmade of resin.

Resilient spring 3 formed of metal wire is housed in movable casing 2 ina slightly contracted condition. Lock part 1C of movable shaft 1 ispassed through substantially elliptical through hole 4A in the center ofmovable member 4 made of metal, so that movable member 4 is locked so asto be axially movable. Movable member 4 is urged rectilinearly by spring3.

Stationary member 6 is made of metal and has central through hole 6Athrough which a tip of cylinder 1B of movable shaft 1 is rotatablypassed. Movable cam 5A of movable member 4 that provides a click feel isin resilient contact with stationary cam 7A of stationary member 6.Movable cam 5B opposite to movable cam 5A is in resilient contact withstationary cam 7B.

Movable shaft 1 is thus passed through movable casing 2, movable member4 and stationary member 6, and C-ring 8 is fixed to lock part 1D ofmovable shaft 1. Opening and closing device 9 is thus formed withmovable shaft 1, movable casing 2 and movable member 4 rotatablyprovided to stationary member 6.

Referring to FIG. 11, which includes side views, a description will beprovided next of the electronic apparatus using the opening and closingdevice 9 described above.

In FIG. 11, stationary housing 25 is formed with, at its top surface,operating part 27 formed of a plurality of keys. Movable housing 26 isformed with, at its inner surface, display part 28 such as an LCD.Stationary housing 25 and the movable housing are formed of insulatingresin.

Stationary member 6 of opening and closing device 9 is mounted to an endof stationary housing 25, while movable casing 2 is mounted to an end ofmovable housing 26. Movable housing 26 is rotatably supported by openingand closing device 9 so as to be able to open and close relative tostationary housing 25.

Referring to FIG. 11 and FIG. 12, which includes sectional views eachillustrating an essential part in an operating condition, a descriptionwill be provided hereinafter of the opening and closing operation of theabove-structured opening and closing device and the electronic apparatususing this device.

FIG. 11A illustrates movable housing 26 in a closed state where thesurface of movable housing 26 is in contact with the top surface ofstationary housing 25. In this state, movable cam 5A of movable member 4urged by spring 3 engages with stationary cam 7A of stationary member 6,as shown in FIG. 12A, so that opening and closing device 9 is held inthe closed state.

When a user swings movable housing 26 in a direction that opens movablehousing 26 from the closed state against the urging force of spring 3,movable casing 2 locked to movable housing 26 causes movable cam 5A ofmovable member 4 to move toward slope 7C against the urging force ofspring 3 through rotation.

FIG. 11B illustrates movable housing 26 in a half-open state wheremovable housing 26 is swung to a substantially upright position. In thisstate, movable casing 2 causes movable member 4 to rotate with respectto stationary member 6 of opening and closing device 9, as shown in FIG.12B. Accordingly, movable cam 5A moves to flat part 7D of a top surfaceof stationary member 6 through rotation.

FIG. 11C illustrates movable housing 26 in an open state where movablehousing 26 is operated to open with respect to stationary housing 25. Inthis state, movable cam 5B positioned opposite to movable cam 5A engageswith stationary cam 7A, as shown in FIG. 12C, thus maintaining the openstate.

To close movable housing 26 from this open state, the user swingsmovable housing 26 in a direction opposite to the direction describedabove, that is, in the direction that closes movable housing 26. In thisway, movable housing 26 is closed.

With the above-described conventional opening and closing device and theelectronic apparatus using this device, the user can close movablehousing 26 with one hand with relative ease.

To swing movable housing 26 to the open state from the closed state, theuser performs the opening operation against the urging force of spring3. For this reason, the user, for example, holds stationary housing 25with one hand and swings movable housing 26 open with the other hand.The opening operation is thus troublesome.

BRIEF SUMMARY OF THE INVENTION

The present invention aims to provide an opening and closing device,which allows a user to easily perform opening and closing operation withone hand, and also aims to provide an electronic apparatus using thisopening and closing device.

To achieve the above-mentioned object, the present invention has thefollowing structure.

In the opening and closing device of this invention, a movable member iscoupled to a stationary member to be rotatable in opening and closingdirections.

An urging section urges the movable member in the opening direction inan open state and urges the movable member in the closing direction in aclosed state.

A reversing section reverses, in the closed state, the direction theurging section urges the movable member so that the urging directionchanges from the closing direction to the opening direction.

The opening and closing device of this invention further includes amovable casing, coupled to the movable member, for rotating inaccordance with movement of the movable member.

In the opening and closing device of this invention, the movable casing,a spring, the movable member, a slide member, a reversing member, arelease member and the stationary member are shaped into a cylinder andarranged along an axis of the cylinder.

The urging section includes the movable member and the slide member. Themovable member is urged by the spring having one end pressed by themovable casing and includes a movable cam disposed along a side of themovable member. The slide member includes, at a side of one end of theslide member, a stationary cam, opposed to the movable cam, forresiliently contacting the movable cam. This slide member is disposedbetween the movable member and the stationary member.

The movable member is urged in the opening or closing directionaccording to which portion of the stationary cam is in resilient contactwith the movable cam.

The reversing section includes the release member and the reversingmember.

The release member includes a release cam resiliently contacting asupport cam disposed on a side positioned at the other end of the slidemember. This release member is disposed between the slide member and thestationary member. The reversing member is inserted into a hollow partof the slide member and includes a reversing cam.

Rotation of the release member disconnects the release cam from thesupport cam, whereby the slide member slides axially. Accordingly, themovable cam is disconnected from the stationary cam and comes intoresilient contact with the reversing cam. Consequently, the movablemember is urged in the opening direction.

In the opening and closing device of this invention, a release shaft isrotatably passed through the stationary member and connected to therelease member. As the release shaft rotates, the release member isrotated accordingly, whereby the release cam is disconnected from thesupport cam. The opening and closing device thus rotates in the openingdirection.

The electronic apparatus of this invention includes the above-mentionedopening and closing device, and its stationary housing includes at leastone of an operating part and an audio input unit at its top surface. Amovable housing of this electronic apparatus includes at least one of adisplay part and an audio output unit at its surface. The stationarymember of the opening and closing device is coupled to the stationaryhousing, while the movable member is coupled to the movable housing.

The opening and closing device, which allows the user to open and closeeasily with one hand, and the electronic apparatus using this device canthus be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an essential part of an opening andclosing device in accordance with an exemplary embodiment of the presentinvention.

FIG. 2 is an exploded perspective view of the opening and closing devicein accordance with the embodiment.

FIG. 3 is a perspective view of an electronic apparatus in accordancewith the embodiment.

FIGS. 4A, 4B and 4C are side views each illustrating the electronicapparatus in an operating condition in accordance with the embodiment.

FIGS. 5A, 5B, 5C and 5D are sectional developed views of an essentialpart for illustrating operation of the opening and closing device inaccordance with the embodiment.

FIGS. 6A, 6B, 6C and 6D are sectional developed views of the essentialpart of the opening and closing device for illustrating operation inaccordance with the embodiment.

FIG. 7 is an exploded perspective view of an essential part inaccordance with another exemplary embodiment.

FIGS. 8A, 8B and 8C are sectional views of an essential part inaccordance with still another exemplary embodiment.

FIG. 9 is a sectional view of a conventional opening and closing device.

FIG. 10 is an exploded perspective view of the conventional opening andclosing device.

FIGS. 11A, 11B and 11C are side views of an electronic apparatus usingthe conventional opening and closing device.

FIGS. 12A, 12B and 12C are sectional views each illustrating anessential part of the conventional opening and closing device in anoperating condition.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

An exemplary embodiment of the present invention will be demonstratedhereinafter with reference to FIGS. 1–8.

EXEMPLARY EMBODIMENT

FIG. 1 is a perspective view of an essential part of opening and closingdevice 30 in accordance with the exemplary embodiment of the presentinvention.

FIG. 2 is an exploded perspective view of the opening and closingdevice.

In FIGS. 1 and 2, opening and closing device 30 includes movable casing10 and stationary member 21 and also includes spring 11, movable member12, slide member 14, reversing member 17, release member 19, releaseshaft 22 and return spring 23 between movable casing 10 and stationarymember 21.

For explanation, “left” or “right” is hereinafter used to indicate thedirection in the drawings.

Movable casing 10 is made of resin and is substantially cylindrical. Themovable casing 10 has an opening 10A at its left side and includes, inits outer periphery, recessed part 10B, which is shaped like an oblonghole and extends axially from opening 10A. Resilient coiled spring 11formed of metal wire is housed in movable casing 10 in a slightlycontracted condition.

Movable member 12 is urged by spring 11 and is located to the left ofspring 11 so as to be axially movable with projection 12A. Projection12A is provided on a periphery of movable member 12, and is engaged inrecessed part 10B of movable casing 10. The movable member 12 is made ofmetal and is substantially cylindrical. Movable cam 13 projectssubstantially in the form of a triangle and is provided on a left sideof movable member 12.

Slide member 14 is made of metal and is a substantially cylindricalslide member having a hollow part along its axis. Slide member 14 isprovided with, along a border of its right side, stationary cam 15 whichincludes two slopes 15A, 15B adjacent to each other across tip 15C.Movable cam 13 of movable member 12, which is urged by spring 11,resiliently contacts lower slope 15A of stationary cam 15.

As described above, an urging section is formed to includeabove-described spring 11, movable member 12 and slide member 14.

Reversing member 17 is made of metal, substantially cylindrical anddisposed inside the hollow part of slide member 14. Along a border of aright side of reversing member 17, reversing cam 18 formed with upwardlysloping slope 18A is provided in a position opposed to movable cam 13.

Reversing member 17 also includes projection 44 on its outer periphery.This projection 44 engages recessed part 42 within the hollow part ofslide member 14. Projection 44 and recessed part 42 are formed so as toallow slide member 14 to slide axially.

Release shaft 22 is substantially cylindrical, made of metal andprovided with knob 22A at its left end.

Release member 19 is made of metal and includes substantiallytrapezoidal release cam 20 on its right side.

Substantially cylindrical stationary member 21 is made of metal andprovided with, on its left side, engagement part 21A attached to astationary housing of an electronic apparatus. Leg 46 projecting from aleft side of reversing member 17 is fixed into a right side ofstationary member 21.

Leg 46 of reversing member 17 is passed through hole 48 of releasemember 19.

Release shaft 22 is rotatably passed through central through hole 21B ofstationary member 21. Release member 19 is locked to a right end ofrelease shaft 22. The release member 19 is disposed between stationarymember 21 and a combination of slide member 14 and reversing member 17so as to be rotatable to a given angle.

Accordingly, there is a clearance between hole 48 of above-mentionedrelease member 19 and leg 46 of reversing member 17 for allowing releasemember 19 to rotate to the given angle.

Return spring 23 is a resilient torsion coil spring made of metal wireand is disposed between release member 19 and reversing member 17. Endsof return spring 23 are locked to release member 19 and reversing member17, respectively. Return spring 23 urges release member 19 in thedirection of rotation.

Substantially trapezoidal support cam 16 is provided along a border of aleft side of slide member 14. The urging force of spring 11 istransmitted to the support cam 16 via movable cam 13 of movable member12 and stationary cam 15 on the right side of slide member 14. Theurging force of spring 11 causes support cam 16 to resiliently contactrelease cam 20 of release member 19.

When release member 19 is rotated against the urging force of returnspring 23, release cam 20 rotates accordingly, thereby beingdisconnected from support cam 16. Here, slide member 14 slides axiallyleftward, and movable cam 13 comes into resilient contact with slope 18Aof reversing cam 18, moving from slope 15A of stationary cam 15.

A reversing section is formed to include the above-described reversingmember 17, slide member 14, release member 19 and release shaft 22.

Between movable casing 10 and stationary member 21, spring 11, movablemember 12, slide member 14, reversing member 17, release member 19,release shaft 22 and return spring 23 are arranged substantially on thesame axis.

In this way, opening and closing device 30 is configured.

Referring to FIG. 3, which is a perspective view of the electronicapparatus, a description will be provided next of the electronicapparatus using opening and closing device 30 having the abovestructure.

In FIG. 3, the electronic apparatus includes stationary housing 31 andmovable housing 32 each made of insulating resin.

Stationary housing 31 is formed with, at its top surface, operating part33 formed of a plurality of keys, and an audio input unit such as amicrophone. Movable housing 32 is formed with, at its surface, displaypart 34 such as an LCD, and an audio output unit such as a loudspeaker.

Stationary member 21 of opening and closing device 30 is mounted to anend of stationary housing 31, while movable casing 10 is mounted to anend of movable housing 32. Movable housing 32 is rotatably supported byopening and closing device 30 so as to be able to open and closerelative to stationary housing 31.

Referring to FIGS. 4–6, a description will be provided hereinafter ofthe opening and closing operation of the opening and closing device 30having the above structure and the electronic apparatus using thisdevice.

As mentioned earlier, movable cam 13, stationary cam 15, support cam 16,reversing cam 18 and release cam 20 are provided at a periphery of thesubstantially cylindrical construction in three dimensions in reality.However, these elements are shown in developed plan views in FIGS. 5 and6 for easy understanding of the operation of each element.

FIG. 4A illustrates movable housing 32 in a closed state where thesurface of movable housing 32 is in contact with the top surface ofstationary housing 31.

When opening and closing device 30 is in this closed state, movable cam13 of movable member 12, which is urged downward by spring 11 asindicated by arrow F, is in resilient contact with slope 15A ofstationary cam 15, as shown in FIG. 5A. Movable member 12 is thus heldby being urged rightward, that is, in a closing direction indicated byarrow G.

When a user swings movable housing 32 open, movable housing 32 andmovable casing 10 rotate, whereby movable member 12 and movable cam 13move leftward as indicated by arrow H in FIG. 5B against the rightwardurging force of spring 11. Movable cam 13 thus crosses over tip 15C fromslope 15A of stationary cam 15 and comes into resilient contact withslope 15B. Consequently, movable member 12 is urged leftward, that is,in an opening direction.

Then, movable cam 13 resiliently slides over slope 15B of stationary cam15, as shown in FIG. 5C. Here, movable housing 32 shifts from a halfwaystate illustrated by FIG. 4B where movable housing 32 is swung to asubstantially upright position relative to stationary housing 31 to astate illustrated by FIG. 4C where movable housing 32 is opened fullywith respect to stationary housing 31.

In the state where movable housing 32 is opened fully, movable cam 13resiliently contacts a left end of slope 15B of stationary cam 15, asshown in FIG. 5D. Movable housing 32 mounted with movable member 12 isthus held in a state where movable housing 32 is urged leftward, thatis, in the opening direction.

When the user closes movable housing 32 from this open state, movablecam 13 resiliently slides over stationary cam 15 in reverse order, thatis, in order of FIGS. 5C, 5B and 5A. In this way, movable housing 32 isclosed.

A description will be provided next of a case where the user uses thereversing section instead of the hand such as described above to openmovable housing 32 from the closed state.

In the state illustrated by FIG. 4A where movable housing 32 is closed,movable cam 13 of movable member 12 urged by spring 11 is in resilientcontact with slope 15A of stationary cam 15, as shown in FIG. 6A.

When knob 22A of release shaft 22 is turned against the urging force ofreturn spring 23, release member 19 locked to the right end of releaseshaft 22 moves rightward as indicated by arrow J in FIG. 6B. Here,release cam 20 is disconnected from support cam 16, whereby slide member14, urged by movable cam 13, moves axially downward as indicated byarrow K.

Then, movable cam 13 moves from slope 15A of stationary cam 15 and comesinto resilient contact with slope 18A of reversing cam 18. Movable cam13 thus resiliently slides over slope 18A. Here, movable member 12 isurged leftward, that is, in the opening direction indicated by arrow H.Then movable member 12 moves in the opening direction through rotationfrom the state where movable member 12 is urged rightward or in theclosing direction. In this way, movable housing 32 swings open.

When knob 22A of release shaft 22 is released from the turningoperation, release member 19 and release cam 20 move leftward asindicated by arrow M in FIG. 6C by being urged by return spring 23.Consequently, slide member 14 is pushed up as indicated by arrow L viasupport cam 16, thereby returning to its original state.

FIG. 4C illustrates movable housing 32 fully opened with respect tostationary housing 31.

In this state, movable cam 13 resiliently contacts the left end of slope15B of stationary cam 15, as shown in FIG. 6D. Movable housing 32mounted with movable member 12 is thus held in the state where movablehousing 32 is urged leftward, that is, in the opening direction.

According to the present embodiment described above, opening and closingdevice 30 includes the reversing section, formed of release cam 20,reversing cam 18 and others, for reversing the direction the urgingsection urges so that the urging direction changes from the closingdirection to the opening direction.

This structure allows not only opening and closing of movable housing 32by the user's hand but also opening of movable housing 32 through easyoperation of the reversing section. Thus, the opening and closingdevice, which facilitates opening and closing with one hand, and theelectronic apparatus using this device can be obtained.

The elements that form the urging section and the reversing section,including spring 11, movable member 12, slide member 14, reversingmember 17, release member 19 and stationary member 21 are arranged onthe same axis. Thus, the opening and closing device is formed so as tobe small.

An open position and a closed position of movable housing 32 can bedetected in the following manner.

For example, a variable resistor including a contact piece and a carbonelectrode is formed as a detecting element between stationary member 21and movable member 12 or movable casing 10, and the electronic apparatusis provided with a detection circuit connected to this detectingelement.

The detecting element thus detects the open and closed positions ofmovable member 12 or movable housing 32. This enables the apparatus toperform various functions. For example, the display on display part 34can be turned off in the closed state and turned on in the open state.

The detecting element can be a switch, an optical sensor, a magneticsensor or the like instead of the variable resistor.

In the above description, knob 22A of release shaft 22 is turned tooperate the reversing section. However, other various operations of knob22A, including pushing, can effect the operation of the reversingsection.

In the above description, axially extending recessed part 10B having theshape of an oblong hole is provided in the outer periphery of movablecasing 10. This recessed part 10 B engages with projection 12A ofmovable member 12, so that movable casing 10 and movable member 12rotate to the same angle.

In another structure, a movable casing can be rotated to an angle largeror smaller than that of a movable member by sloping a recessed part.

In other words, as shown in FIG. 7, which is an exploded perspectiveview of an essential part, movable casing 29 is formed with recessedpart 29B, which is shaped like an oblong hole and sloped relative to theaxial direction from opening 29A. Projection 24A of movable member 24engages this recessed part 29B.

In this structure, movable member 24 rotates while moving axially withrespect to a stationary member (not shown). Here, movable casing 29rotates to the angle larger or smaller than the rotation angle ofmovable member 24 in accordance with the sloping direction.

For example, in cases where, as shown in FIG. 7, recessed part 29B issloped in an upper-right direction from opening 29A, when movable member24 moves leftward within movable casing 29 while rotating upward,movable casing 29, having recessed part 29B urged by projection 24A ofmovable member 24, rotates upward to the angle larger than the rotationangle of movable member 24.

When movable member 24 moves rightward while rotating downward, theangle of downward rotation of movable casing 29 is smaller than therotation angle of movable member 24. A difference between these rotationangles varies, depending on an angle of inclination of recessed part29B.

In cases where recessed part 29B is sloped in lower-right direction fromopening 29A, the relationship between the angle of upward rotation andthe angle of downward rotation is the reverse one of the relationshipdescribed above.

As described above, sloping recessed part 29B of movable casing 29 withrespect to the axial direction causes movable casing 29 to rotate to theangle larger or smaller than that of movable member 24 in accordancewith the sloping direction when the movable member rotates while movingaxially with respect to the stationary member. For this reason, amovable housing of an electronic apparatus that is mounted with thismovable casing 29 can be opened and closed to a large or small angle inan arbitrary direction.

Instead of being formed into the oblong hole in the outer periphery ofmovable casing 10 or 29, the recessed part may be provided in the formof a groove in an inner periphery of the movable casing.

In the above description, the elements such as spring 11, movable member12, slide member 14, reversing member 17, release member 19 andstationary member 21 are arranged on the same axis to form the urgingsection and the reversing section.

Alternatively, the opening and closing device may have the followingstructure.

As shown in FIG. 8, one end of resilient coiled spring 37 formed ofmetal wire is held by stationary member 35 with spring 37 in a littlecontracted condition. The other end of spring 37 is held by movablemember 36 rotatably locked to stationary member 35.

FIG. 8A illustrates movable member 36 in a closed state with respect tostationary member 35. In this state, reversing section 38 urges spring37 to a halfway state illustrated by FIG. 8B, whereby the urging forceof spring 37 that acts on movable member 36 is reversed so that theurging direction changes from the closing direction to the openingdirection.

Movable member 36 is thus held in an open state, as shown in FIG. 8C bybeing urged in the opening direction by spring 37.

Opening and closing device 30 described above can be mounted to theelectronic apparatus such as shown in FIG. 3. The electronic apparatusmentioned here includes stationary housing 31 and movable housing 32.

Stationary housing 31 is formed with at least one of the operating partand the audio input unit at its top surface. Movable housing 32 isformed with at least one of the display part and the audio output unitat its surface. The end of movable housing 32 is mounted with themovable casing of the opening and closing device. Thus, the user caneasily open and close this electronic apparatus with one hand.

INDUSTRIAL APPLICABILITY

According to the present invention described above, the opening andclosing device, which allows the user to easily perform opening andclosing operation with one hand, and the electronic apparatus using thisopening and closing device can be obtained.

1. An opening and closing device comprising: a stationary member; amovable member coupled to said stationary member so as to be rotatablein opening and closing directions; an urging section for urging saidmovable member in the opening direction in an open state and urging saidmovable member in the closing direction in a closed state; a reversingsection for reversing, in the closed state, a direction that said urgingsection urges said movable member so that the urging direction changesfrom the closing direction to the opening direction; and a movablecasing connected to said movable member, said movable casing beingoperable to rotate in accordance with movement of said movable member,wherein: said urging section comprises: said movable member urged by aspring having an end pressed by said movable casing, said movable memberincluding a movable cam disposed along a side of said movable member;and a stationary cam at a first end of a slide member, said stationarycam being opposed to said movable cam, for resiliently contacting saidmovable cam, said slide member being disposed between said movablemember and said stationary member; said movable member is being arrangedso as to be urged in one of the opening and closing directions accordingto which portion of said stationary cam is in resilient contact withsaid movable cam; said reversing section comprises: a release memberincluding a release cam resiliently contacting a support cam disposed ona second end of said slide member, said release member being disposedbetween said slide member and said stationary member; and a reversingmember inserted into a hollow part of said slide member, said reversingmember including a reversing cam; and wherein said movable casing, saidspring, said movable member, said slide member, said reversing member,said release member and said stationary member are shaped into acylinder and arranged along an axis of said cylinder, and due torotation of said release member, said release cam is disconnected fromsaid support cam, said slide member slides axially, said movable cam isdisconnected from said stationary cam and comes into resilient contactwith said reversing cam, and consequently, said movable member is urgedin the opening direction.
 2. The opening and closing device of claim 1,further comprising: a release shaft rotatably passed through saidstationary member and connected to said release member such that arotation of said release shaft rotates said release member fordisconnecting said release cam from said support cam.
 3. The opening andclosing device of claim 1, wherein: (i) said stationary cam includesfirst and second slopes, said movable member is being arranged so as tobe urged in the opening direction when said movable cam resilientlycontacts said first slope, and said movable member is being arranged soas to be urged in the closing direction when said movable camresiliently contacts said second slope; and (ii) said reversing camincludes a third slope, and said movable member being arranged so as tobe urged in the opening direction when said movable cam resilientlycontacts said third slope of said reversing cam.
 4. An electronicapparatus comprising: the opening and closing device of claim 1; astationary housing including at least one of an operating part and anaudio input unit at a top surface of said stationary housing; and amovable housing including at least one of a display part and an audiooutput unit at a surface of said movable housing, wherein saidstationary member is connected to said stationary housing, and saidmovable member is connected to said movable housing.
 5. The opening andclosing device of claim 2, wherein: (i) said stationary cam includesfirst and second slopes, said movable member being arranged so as to beurged in the opening direction when said movable cam resilientlycontacts said first slope, and said movable member is being arranged soas to be urged in the closing direction when said movable camresiliently contacts said second slope; and (ii) said reversing camincludes a third slope, and said movable member being arranged so as tobe urged in the opening direction when said movable cam resilientlycontacts said third slope of said reversing cam.
 6. The opening andclosing device of claim 1, further comprising: a projection provided ona periphery of said movable member, wherein said movable casing includesa recessed part for engaging said projection, said movable member andsaid movable casing are shaped into a cylinder, said movable member ishoused in said movable casing so as to be movable in an axial direction,and said recessed part is sloped relative to the axial direction.
 7. Theopening and closing device of claim 2, further comprising: a projectionprovided on a periphery of said movable member, wherein said movablecasing includes a recessed part for engaging said projection, saidmovable member and said movable casing are shaped into a cylinder, saidmovable member is housed in said movable casing so as to be movable inan axial direction, and said recessed part is sloped relative to theaxial direction.
 8. The opening and closing device of claim 3, furthercomprising: a projection provided on a periphery of said movable member,wherein said movable casing includes a recessed part for engaging saidprojection, said movable member and said movable casing are shaped intoa cylinder, said movable member is housed in said movable casing so asto be movable in an axial direction, and said recessed part is slopedrelative to the axial direction.
 9. The opening and closing device ofclaim 5, further comprising: a projection provided on a periphery ofsaid movable member, wherein said movable casing includes a recessedpart for engaging said projection, said movable member and said movablecasing are shaped into a cylinder, said movable member is housed in saidmovable casing so as to be movable in an axial direction, and saidrecessed part is sloped relative to the axial direction.
 10. The openingand closing device of claim 1, further comprising: a release shaftconnected to said release member such that a rotation of said releaseshaft rotates said release member to thereby disconnect said release camfrom said support cam.
 11. The opening and closing device of claim 1,further comprising: a projection provided on a periphery of said movablemember, wherein said movable casing includes a recessed part forengaging said projection, said movable member and said movable casingare shaped into a cylinder, said movable member is housed in saidmovable casing so as to be movable in an axial direction of said movablecasing, and a longitudinal axis of said recessed portion is slopedrelative to the axial direction of said movable casing.
 12. An openingand closing device comprising: a movable casing having a substantiallycylindrical shape; a stationary member arranged along an axis of saidmovable casing; a spring having one end pressed by said movable casing;a movable member arranged to have a first end in contact with saidspring in a direction of the axis of said movable casing such that saidmovable member is urged by said spring along the axis of said movablecasing, said movable member having a movable cam at a second end in thedirection of the axis of said movable casing, said movable member beingrotatable around the axis of said movable casing in an opening directionand a closing direction; a slide member operable to slide along the axisof said movable casing, said slide member having a hollow portion, astationary cam in resilient contact with said movable cam at a first endof said slide member with respect to the direction of the axis of saidmovable casing, and a support cam at a second end of said slide memberwith respect to the direction of the axis of said movable casing; areversing member in the hollow portion of said slide member, saidreversing member having a reversing cam operable to resiliently contactsaid movable cam; and a release member in resilient contact with astationary member at a first end with respect to the direction of theaxis of said movable casing, said release member including a release camat a second end with respect to the direction of the axis of saidmovable casing, said release cam being operable to resiliently contactsaid support cam, wherein said movable member, said slide member, saidreversing member and said release member are arranged along the axis ofsaid movable casing, and said movable member, said slide member, saidreversing member, and said release member are arranged andinterconnected such that, when said release member is rotated: saidrelease cam is disconnected from said support cam; said slide memberslides along the axis of said movable casing; said movable cam isdisconnected from said stationary cam and comes into resilient contactwith said reversing cam; and said movable member is thereby urged in theopening direction.
 13. The opening and closing device of claim 12,further comprising: a release shaft connected to said release membersuch that a rotation of said release shaft roatates said release memberto thereby disconnect said release cam from said support cam.
 14. Theopening and closing device of claim 12, wherein: (i) said stationary camincludes first and second slopes, said movable member being arranged soas to be urged in the opening direction when said movable camresiliently contacts said first slope, and said movable member beingarranged so as to be urged in the closing direction when said movablecam resiliently contacts said second slope; and (ii) said reversing camincludes a third slope, and said movable member being arranged so as tobe urged in the opening direction when said movable cam resilientlycontacts said third slope of said reversing cam.
 15. The opening andclosing device of claim 12, further comprising: a projection provided ona periphery of said movable member, wherein said movable casing includesa recessed part for engaging said projection, said movable member andsaid movable casing are shaped into a cylinder, said movable member ishoused in said movable casing so as to be movable in an axial direction,and said recessed part is sloped relative to the axial direction.
 16. Anelectronic apparatus comprising: the opening and closing device of claim12; a stationary housing including at least one of an operating part andan audio input unit at a top surface of said stationary housing; and amovable housing including at least one of a display part and an audiooutput unit at a surface of said movable housing, wherein saidstationary member is connected to said stationary housing, and saidmovable member is connected to said movable housing.
 17. The opening andclosing device of claim 12, further comprising: a projection provided ona periphery of said movable member, wherein said movable casing includesa recessed part for engaging said projection, said movable member andsaid movable casing are shaped into a cylinder, said movable member ishoused in said movable casing so as to be movable in an axial directionof said movable casing, and a longitudinal axis of said recessed portionis sloped relative to the axial direction of said movable casing.